[Ubuntu] Fix gpg resource limits and missing keys

Fix-Ubuntu-GPG-Resource-Limits.txt

### The solution is to empty the "/etc/apt/trusted.gpg.d", run "apt-get update" and then manually adding every key it blocked on to the main "/etc/apt/trusted.gpg" keyring with apt-key adv as described.
### FROM https://medium.com/@foxoman/ubuntu-tip-fix-gpg-resource-limits-and-missing-keys-ec7f1da4c02
### TESTED ON Ubuntu 14.04.4

sudo mv /etc/apt/trusted.gpg.d/ /etc/apt/trusted.gpg.d.backup
sudo mkdir /etc/apt/trusted.gpg.d
sudo chmod 755 /etc/apt/trusted.gpg.d

sudo apt-get update 2> /tmp/keymissing; for key in $(grep "NO_PUBKEY" /tmp/keymissing |sed "s/.*NO_PUBKEY //"); do echo -e "\nProcessing key: $key"; sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys $key ; done


# Sources:

#    http://elementaryos.stackexchange.com/questions/96/how-to-fix-gpg-keyblock-resource-etc-apt-trusted-gpg-d-key-gpg-resource-l
#    http://askubuntu.com/questions/127326/how-to-fix-missing-gpg-keys